The present invention relates to color gamut mapping different size color gamuts for printing.
The term “color gamut” or gamut generally is used to describe the complete range of colors an image contains or a device is able to render. It is sometimes referred to as a color gamut or the gamut color space associated with a printer or screen display device. Gamut mapping an image onto a screen or printer generally requires adjusting the colors of the image to fit in the constrained color gamut of the screen or printer. In some cases, the image being displayed does not have a wide range of colors and therefore does not fill or utilize the wider range of colors in the printer gamut or even the screen gamut. In other cases, the colors in an image are outside the narrow color gamut of a displaying device but can be printed on a color printer having a wider gamut.
These wider gamut color printers have grown in popularity as consumers desire to achieve professional or at least “prosumer” quality color printing. Newer applications are being created that send wider gamut images directly to these wider gamut printers and other output devices. The peer-to-peer color workflow used in these applications is advantageous as the wider printer gamuts are not limited by the intermediary and narrower gamut of a monitor or other display device. For example, cameras, palm tops, cell phones, Internet terminals and digital picture frames generate images using wider gamuts in YCC, Adobe RGB, bgRGB, scRGB, CIELAB, e-sRGB or ROMM digital representations. These devices are imaging enabled and connected to a printer directly or through a network or Internet connection and do not need to display images using a narrow gamut like sRGB.
Nonetheless, there does remain many legacy systems and applications that continue to use a workflow that transmits colors using the narrower (sRGB) and then gamut maps to the wider color gamut of a color printer. Even new systems and applications work in the more display-centric workflow using the sRGB gamut as the sRGB color space has become an industry standard in color transmission. In general, the sRGB narrow gamut will continue to serve the consumer market as it is inexpensive to implement, computationally efficient, and transparent to the end user. Printing with both sRGB, a relatively narrow gamut, and wider gamuts will likely coexist for the future as consumers very slowly migrate to wider gamut technologies.
Unfortunately, the coexistence of narrow and wide gamut technologies makes it difficult to print color images consistently on wide gamut printers. This is due to differences in gamut mapping from the newer wider gamut and the narrower sRGB technologies. Gamut mapping from a wider gamut to the printer gamut produces different results than gamut mapping from the sRGB used on a display to the same printer gamut.
In the first instance, a wide gamut application performs processing on the wide gamut information and then outputs the image data to the printer by gamut mapping between the wide gamut and the printer gamut; narrow gamut sRGB applications process narrow gamut information but instead perform gamut mapping from the narrow gamut to the printer gamut. The printed output differs on conventional systems due to the different types of gamut mapping and transformations performed. For example, conventional systems using sRGB cannot accurately represent the numerous dark chromatic colors as they are outside the narrow gamut space of sRGB.
There remains a need to be able to print color images consistently whether gamut mapping from a narrow gamut like sRGB or a wider gamut to the gamut of a printer.
Like reference numbers and designations in the various drawings indicate like elements.